1. Field of the Invention
The present invention relates to a network system for constructing a home network environment, and more particularly, to a data transmitting node and a network inter-connection node suitable for use in the home network environment.
2. Description of the Background Art
In recent years, there is a rapid trend for digitalizing electronic instruments as exemplified by the term xe2x80x9cmulti-mediaxe2x80x9d, and this trend is already noticeable in the office environment.
More specifically, in terms of hardware, this trend has been materialized in forms of introduction of PCs, digitalization of OA devices and formation of networks among them. Also, in terms of software, this trend has been expanding to cover the basic functions of hosts (which are progressively light-sized and transferred to PCs), the application software such as the word-processing software, the spreadsheet software, etc., and the Internet application such as the WWW.
The similar trend can also be seen in the home environment. Namely, even in the home environment, this trend for digitalization has been steadily progressed in forms of digitalization of AV devices (DVD, digital VTR, digital video camera, etc.), digitalization of broadcasting, and Internet access such as OCN.
Similarly as in a case of the office environment, this trend is expected to progress toward the formation of networks in future. Namely, it is expected that the technologies of various fields such as information processing, communication and broadcasting will be unified by the digitalization, and inter-mixed with each other by the formation of networks.
There are many candidates for the network technologies in this direction. For example, the Ethernet has overwhelming records of the actual use in the office environment and is probably the most promising candidate even for the home PC network. Also, the ATM is another serious contender because of the general consensus among the infra-structure constructors (telephone companies, CATV companies, etc.) to keep constructing the infra-structures based on this technology in view of the advantageous characteristics of the ATM such as its fast, real-time, and wide bandwidth properties.
In addition to these candidates, the network technology (bus technology) called IEEE 1394 has been attracting much attentions recently. This IEEE 1394 has several remarkable characteristics such as its fast, real-time (QOS guaranteed), and plug-and-play properties, so that there is a high expectation especially among the AV industries on the IEEE 1394 as the most promising candidate for a future scheme for inter-connecting digital AV devices. This vogue has also instigated much interests to the IEEE 1394 from the computer industries as well.
In the initial phase, it is expected that the inter-connection of the home use digital devices will be realized by these various network technologies in conjunction with the spread of-the home use digital devices, depending on preferences and demands of the users, and in this way prototype digital networks will be gradually built up inside each home.
In the second phase, there will be demands for inter-connecting these digital networks together. For example, there will be a desire to inter-connect an AV device connected to the 1394 network of a guest room on the first floor with another AV device connected to the 1394 network of a private room on the second floor in order to realize the dubbing or the cooperative operation between these AV devices.
However, in order to meet the expected demands of this second phase, the following problems must be addressed and resolved.
(1) The 1394 network is not suited for a large scale installation. For example, its cable length is limited to 4.5 m, so that the wiring across rooms will be difficult. Also, the plug-and-play function of the 1394 has the side-effect that the on-going communication will be instantaneously disconnected whenever someone connects to or disconnects from the 1394. When the wiring of the 1394 across rooms is attempted, there will be an inconveniency in that an action made in one room would affect another room in a form of the instantaneous disconnection of the on-going communication because of its xe2x80x9cbus resetxe2x80x9d.
(2) The standardization of the specification for xe2x80x9c1394 bridgexe2x80x9d as the inter-connection protocol/scheme for the 1394 is currently in progress at the IEEE which is the standardization committee for the 1394. However, the standard specification is expected to be a very complicated one that requires the scalability and incorporates a concept of call set up, and it is also expected that a considerable amount of time will be needed before the standard specification can be solidified.
(3) The home network will not necessarily be limited to just the 1394, so that it is preferable to construct the home network according to a scheme that can inter-connect various types of networks. However, no such a network architecture has been proposed so far.
(4) As a known technique for inter-connecting various networks, there is the Internet protocol. However, this scheme is difficult to set up, manage and maintain for the layman, and it also requires the server management, so that in its currently available form it is not suitable for an inter-connection scheme intended for use in the home network which is expected to deal with a rather limited number of terminals.
On the other hand, in recent years, rapid progresses made in the communication technology such as Internet are attracting much attentions from various fields, and issues such as introduction of LAN or connection of that to WAN or Internet are much discussed mainly among companies and universities.
These technological innovations are highly likely to change the network environment surrounding our homes. Namely, with the spread of various digital devices such as PC, DVD, digital set-top box and so on in our homes, demands for inter-connecting them through a digital network inevitably arises. Currently, IEEE 1394 bus is attracting much attentions from various fields, especially among AV vendors, as a prime candidate for such a digital network for home use.
This IEEE 1394 bus can be used as a high speed digital network of 100, 200 or 400 Mbps, and has several remarkable characteristics including plug-and-play properties, synchronous transfer function using isochronous channel, etc., as already mentioned above.
Meanwhile, rapid technological innovations are also made in the so called access network for homes. Namely, notable progresses have been made in high speed network technologies such as CATV, ADSL (Asymmetric Digital Subscriber Line) and FTTH (Fiber-To-The-Home) as well as network services such as Internet, and so on. In particular, the Internet technology has promoted many remarkable techniques including its fast implementation, guarantee of QOS (Quality Of Service) using network layer level signaling protocol such as RSVP (Resource Reservation Protocol), multicast, and so on.
In near future where these techniques are realized on Internet, transfer of some information that require high speed and realtime characteristics such as video transfer to homes may very well be carried out through Internet. This is because Internet can store virtually infinite amount of information so that it is only natural for Internet users to come to expect acquisition through Internet of the above noted information which has conventionally been acquired from terrestrial or satellite broadcasting and the like.
However, when exchanges of information through Internet are attempted by connecting home digital devices through the access network, the following problems will be encountered.
(1) Currently, a scheme for distributing Internet data over IEEE 1394, i.e., IP-over-1394, is discussed by various groups, but these discussions still remain at a level of the so called address resolution scheme. On the other hand, there is a proposition of a signaling protocol such as RSVP for carrying out data exchanges with guaranteed communication quality on Internet. However, a scheme for operating such a network layer signaling protocol on IEEE 1394 has not been standardized so that mapping to a transfer scheme that does not guarantee communication quality is the only available option for IEEE 1394.
Consequently, even when the above noted signaling protocol is executed, data will be transferred over IEEE 1394 on the best effort basis (more specifically, through asynchronous channel) so that the end-to-end communication quality cannot be guaranteed.
(2) In the case of transmission and reception of IP multicast on IEEE 1394 bus, the use of isochronous channel or asynchronous stream of IEEE 1394 can be considered in order to minimize traffic on IEEE 1394 bus. However, when two or more devices tries to subscribe for the same IP multicast at the same time, there is a possibility for these two or more devices to reserve different channels separately so that the efficient utilization of communication resource cannot be realized.
Moreover, there is no mechanism for enabling synchronized recognition of correspondence between reserved channel and IP multicast address by a transmitting side and a receiving side.
It is therefore an object of the present invention to provide a data transmitting node and a network inter-connection node which are capable of resolving the above noted problems and which are therefore suitable for use in the home network environment.
It is another object of the present invention to provide a communication device capable of realizing communication that guarantees communication quality in an inter-connected network environment even on IEEE 1394, by specifying a scheme for applying RSVP to IEEE 1394 bus.
It is another object of the present invention to provide a communication device capable of carrying out IP multicast by utilizing communication resource efficiently, and enabling recognition of correspondence between reserved channel and IP multicast address by a transmitting side and a receiving side in synchronization, in a network of broadcast type such as IEEE 1394.
According to one aspect of the present invention, there is provided a data transmitting node connected with a physical network, comprising: a first transmission unit for transmitting a control message in a case of transmitting information data to a receiving node through connected with the physical network or another physical network, the control message including an IP address information of a data transmission destination, a header/channel information dependent on the physical network, and an information indicating that the information data to be transmitted according to the header/channel information is data in an upper layer of an IP layer; and a second transmission unit for transmitting the information data to the receiving node, the information data containing the header/channel information and data of the upper layer without IP packet encapsulation.
In this aspect of the present invention, it becomes possible to explicitly notify a network connection device on a communication path that the information data that pass through a communication path established by the control message are not IP packets so that they should be forwarded by a datalink layer processing alone without forwarding them to the so called IP processing unit for carrying out the routing processing of IP packets.
Namely, by notifying a header/channel information according to which the information data is to be transmitted later and an IP address of the receiving node to the network connection device, it becomes possible to notify that a transfer destination of the subsequently transmitted information data which has this header/channel information (datalink layer identifier) is the IP address of the receiving node, so that the network connection device on the communication path can establish the communication path (datalink layer communication path) up to the receiving node at the datalink layer level.
In addition, by using the IP address, it becomes possible to realize an address system which can be commonly used even under an environment in which a plurality of types of physical networks are inter-connected, so that it becomes possible to carry out the data transmission and the control message transmission with respect to nodes belonging to physical networks of different transmission schemes.
Moreover, it is possible to explicitly notify the network connection device that the information data that pass through the communication path are not IP packets but the packets in the upper layer than the IP layer, so that it can be expected that the network connection device will transfer the information data on the communication path to the receiving node without applying the so called IP routing processing, and therefore it becomes possible to realize the transmission of the so called raw data such as MPEG video and speech data.
Also, in this aspect of the present invention, the control message may command to a network inter-connection node for connecting said physical network and a next physical network a registration of a correspondence between the header/channel information dependent on said physical network and a header/channel information dependent on the next physical network.
This defines the operation of the control message in this aspect of the present invention.
Also, in this aspect of the present invention, the data transmitting node may further comprises: a reception unit for receiving digital video and/or digital audio data; wherein the second transmission unit transmits the digital video and/or digital audio data received by the reception unit as the information data, by formatting the digital video and/or digital audio data into a transmission format for said physical network.
In this aspect of the present invention, in a case of receiving the raw or MPEG coded video/speech data and forwarding the received data to a specific receiving node, as in a case of a set-top box for the digital satellite broadcast, the digital CATV, or the digital terrestrial broadcast, it becomes possible to realize this data forwarding by formatting the received data into a format of a physical network.
According to another aspect of the present invention, there is provided a network inter-connection node for transmitting information data received from one physical network to another physical network, comprising: a reception unit for receiving a first control message from said one physical network, the first control message containing an IP address information of a data transmission destination, a first header/channel information dependent on said one physical network, and an information indicating that an information data to be transmitted according to the first header/channel information is data in an upper layer of a protocol layer corresponding to the IP address information; a first transmission unit for transmitting a second control message to said another physical network when the reception unit receives the first control message, the second control message containing the IP address information, a second header/channel information dependent on said another physical network which is obtained from the IP address information, and the information indicating that the information data to be transmitted according to the second header/channel information is data in the upper layer; a memory unit for storing a correspondence between the first header/channel information and the second header/channel information; and a second transmission unit for obtaining the second header/channel information corresponding to the first header/channel information according to the correspondence stored in the memory unit when the information data containing the first header/channel information is received from said one physical network, attaching the second header/channel information to the information data, and transmitting the information data to said another physical network, the information data containing data of the upper layer without IP packet encapsulation.
In this aspect of the present invention, the information data containing the first header/channel information are the packets in the upper layer than the IP layer. Consequently, each network connection device on the communication path can recognize that the information data that pass through a communication path established by the control message are not IP packets so that there should be a setting by which they can be forwarded by a datalink layer processing alone without forwarding them to the so called IP processing unit for carrying out the routing processing of IP packets, and make this setting to the second transmission unit. As a result, it becomes possible to realize a transfer of arbitrary data such as MPEG video and speech data in the IP network environment.
Also, in this aspect of the present invention, the first control message may command a registration of a correspondence between the first header/channel information and the second header/channel information, and the second control message may command to a receiving node or a network inter-connection node for connecting said another physical network and a third physical network a registration of a correspondence between the second header/channel information and a header/channel information dependent on said third physical network.
This defines the operations of the first and second control messages in this aspect of the present invention.
According to another aspect of the present invention, there is provided a data transmitting node connected with a physical network, comprising: a first transmission unit for transmitting a control message in a case of transmitting information data to a receiving node connected with the physical network or another physical network, the control message including an IP address information of a data transmission destination, a header/channel information dependent on the physical network, and an information indicating a required communication resource; and a second transmission unit for transmitting the information data containing the header/channel information for which the required communication resource is reserved, to the receiving node.
In this aspect of the present invention, it becomes possible to explicitly notify a network connection device on a communication path that the information data that pass through a communication path established by the control message are requiring this much of the communication resource amounts so that this communication resource amounts should be reserved in a case of acquiring the communication resources (connections, channels, etc.) of the datalink that constitutes this communication path.
In addition, the IP address is used as an address system so that it can be realized under the inter-connection environment of arbitrary combination of mutually different datalink layers and therefore it becomes possible to establish the communication path while reserving the communication resources under an arbitrary inter-connected network environment.
Also, in this aspect of the present invention, the control message may command to a network inter-connection node for connecting said physical network and a next physical network a registration of a correspondence between the header/channel information dependent on said physical network and a header/channel information dependent on the next physical network for which the required communication resource is reserved.
This defines the operation of the control message in this aspect of the present invention.
Also, in this aspect of the present invention, the data transmitting node may further comprises: a reception unit for receiving digital video and/or digital audio data; wherein the second transmission unit transmits the digital video and/or digital audio data received by the reception unit as the information data, by formatting the digital video and/or digital audio data into a transmission format for said physical network.
In this aspect of the present invention, in a case of receiving the raw or MPEG coded video/speech data and forwarding the received data to a specific receiving node, as in a case of a set-top box for the digital satellite broadcast, the digital CATV, or the digital terrestrial broadcast, it becomes possible to realize this data forwarding by formatting the received data into a format of a physical network.
According to another aspect of the present invention, there is provided a network inter-connection node for transmitting information data received from one physical network to another physical network, comprising: a reception unit for receiving a first control message from said one physical network, the first control message containing an IP address information of a data transmission destination, a first header/channel information dependent on said one physical network, and an information indicating a required communication resource; a first transmission unit for transmitting a second control message to said another physical network when the reception unit receives the first control message, the second control message containing a second header/channel information dependent on said another physical network which is obtained from the IP address information, and the information indicating the required communication resource; an establishing unit for establishing a communication path with respect to a receiving node or a next network inter-connection node for connecting said another physical network and a third physical network, the communication path having the second header/channel information with the required communication resource; a memory unit for storing a correspondence between the first header/channel information and the second header/channel information; and a second transmission unit for obtaining the second header/channel information corresponding to the first header/channel information according to the correspondence stored in the memory unit when the information data containing the first header/channel information is received from said one physical network, attaching the second header/channel information to the information data, and transmitting the information data to said another physical network.
In this aspect of the present invention, each network connection device on the communication path can recognize that the information data that pass through a communication path established by the control message are requiring this much of the communication resource amounts so that this communication resource amounts should be reserved in a case of acquiring the communication resources (connections, channels, etc.) of the datalink that constitutes this communication path, establish the datalink layer connection having this communication resource amounts by the establishing unit, and make a corresponding setting to the second transmission unit.
In addition, the IP address is used as an address system so that it can be realized under the inter-connection environment of arbitrary combination of mutually different datalink layers and therefore it becomes possible to establish the communication path while reserving the communication resources under an arbitrary inter-connected network environment.
Also, in this aspect of the present invention, the first control message may command a registration of a correspondence between the first header/channel information and the second header/channel information, and the second control message may command to the receiving node or the next network inter-connection node a registration of a correspondence between the second header/channel information and a header/channel information dependent on said third physical network.
This defines the operations of the first and second control messages in this aspect of the present invention.
According to another aspect of the present invention, there is provided a data transmitting node connected with a physical network, comprising: a first transmission unit for transmitting a control message in a case of transmitting information data to a receiving node connected with the physical network or another physical network, the control message including an IP address information of a data transmission destination, a header/channel information dependent on the physical network, and an information on a format of the information data to be transmitted according to the header/channel information; and a second transmission unit for transmitting the information data in said format which contains the header/channel information, to the receiving node.
In this aspect of the present invention, it becomes possible to explicitly notify a network connection device on a communication path that the information data that pass through a communication path established by the control message will be in this format (such as MPEG, JPEG, etc.) so that they should be forwarded by a datalink layer processing alone without forwarding them to the so called IP processing unit for carrying out the routing processing of IP packets, and a transfer according to the format transfer scheme depending on the datalink layer of a transfer target physical network should be made.
For example, in a case of MPEG, it becomes possible to urge the setting by which the MPEG data can be transferred in a format depending on the datalink layer, such as xe2x80x9cMPEG-over-ATMxe2x80x9d defined by the ATM forum in while being transferred through the ATM network, and xe2x80x9cMPEG-over-1394xe2x80x9d defined by the IEC 61883 while being transferred through the IEEE 1394 bus.
Also, in this aspect of the present invention, the control message may command to a network inter-connection node for connecting said physical network and a next physical network a registration of a correspondence between the header/channel information dependent on said physical network and the header/channel information dependent on the next physical network.
This defines the operation of the control message in this aspect of the present invention.
Also, in this aspect of the present invention, the data transmitting node may further comprises: a reception unit for receiving digital video and/or digital audio data; wherein the second transmission unit transmits the digital video and/or digital audio data received by the reception unit as the information data, by formatting the digital video and/or digital audio data into said format.
In this aspect of the present invention, in a case of receiving the raw or MPEG coded video/speech data and forwarding the received data to a specific receiving node, as in a case of a set-top box for the digital satellite broadcast, the digital CATV, or the digital terrestrial broadcast, it becomes possible to realize this data forwarding by formatting the received data into a format of a physical network.
According to another aspect of the present invention, there is provided a network inter-connection node for transmitting information data received from one physical network to another physical network, comprising: a reception unit for receiving a first control message from said one physical network, the first control message containing an address information of a data transmission destination, a first header/channel information dependent on said one physical network, and an information on a format of the information data to be transmitted according to the first header/channel information; a first transmission unit for transmitting a second control message to said another physical network when the reception unit receives the first control message, the second control message containing the address information, a second header/channel information dependent on said another physical network which is obtained from the address information, and the information on a format of the information data to be transmitted according to the second header/channel information; a memory unit for storing a correspondence between the first header/channel information and the second header/channel information; a conversion unit for converting a transmission format of the information data to be transmitted from a transmission format in the said one physical network to a transmission format in said another physical network; and a second transmission unit for obtaining the second header/channel information corresponding to the first header/channel information according to the correspondence stored in the memory unit when the information data containing the first header/channel information is received from said one physical network, attaching the second header/channel information to the information data, and transmitting the information data to said another physical network.
In this aspect of the present invention, each network connection device on the communication path can recognize that the information data that pass through a communication path established by the control message will be in this format (such as MPEG, JPEG, etc.) so that they should be forwarded by a datalink layer processing alone without forwarding them to the so called IP processing unit for carrying out the routing processing of IP packets, and there is a need to carry out the format conversion in order to transfer according to the format transfer scheme depending on the datalink layer of a transfer target physical network, and make necessary settings to the conversion unit and the second transmission unit.
Also, in this aspect of the present invention, the first control message may command a registration of a correspondence between the first header/channel information and the second header/channel information, and the second control message may command to a receiving node or a network inter-connection node for connecting said another physical network and a third physical network a registration of a correspondence between the second header/channel information and a header/channel information dependent on said third physical network.
This defines the operations of the first and second control messages in this aspect of the present invention.
Also, in this aspect of the present invention, the information data to be transmitted by the second transmission unit may be MPEG data, and the conversion unit may convert the transmission format of the MPEG data from a transmission format for the MPEG data in said one physical network to a transmission format for the MPEG data in said another physical network.
In this aspect of the present invention, by this format conversion by the conversion unit, it becomes possible to transfer the MPEG data in a format depending on the datalink layer, such as xe2x80x9cMPEG-over-ATMxe2x80x9d defined by the ATM forum in while being transferred through the ATM network, and xe2x80x9cMPEG-over-1394xe2x80x9d defined by the IEC 61883 while being transferred through the IEEE 1394 bus.
According to another aspect of the present invention, there is provided a data transmitting node connected with an IEEE 1394 bus, comprising: a first transmission unit for transmitting a control message in a case of transmitting information data to a receiving node connected with another physical network, the control message including an address information of a data transmission destination, and an isochronous channel number or a register offset indicating an isochronous channel of said IEEE 1394 bus; and a second transmission unit for transmitting the information data in forms of IEEE 1394 packets containing the isochronous channel number or the register offset, onto the isochronous channel.
In this aspect of the present invention, it becomes possible to explicitly notify a transfer target of the received data to a network connection device on a communication path connected to the IEEE 1394 bus, in such a manner that the information data entering from that isochronous channel number at the IEEE 1394 interface to which this control message is entered will be data destined to that data transmission destination address.
In addition, it also becomes possible to explicitly notify that the information data that pass through that isochronous channel should be forwarded to a next hop network channel by a datalink layer processing alone without forwarding them to the so called IP processing unit for carrying out the routing processing of IP packets.
Also, in this aspect of the present invention, the control message may command to a network inter-connection node for connecting said IEEE 1394 bus and a next physical network a registration of a correspondence between the isochronous channel number of the register offset and a header/channel information dependent on the next physical network.
This defines the operation of the control message in this aspect of the present invention.
Also, in this aspect of the present invention, the data transmitting node may further comprises: a reception unit for receiving digital video and/or digital audio data; wherein the second transmission unit transmits the digital video and/or digital audio data received by the reception unit as the information data, by formatting the digital video and/or digital audio data into an IEEE 1394 transmission format.
In this aspect of the present invention, in a case of receiving the raw or MPEG coded video/speech data and forwarding the received data to a specific receiving node, as in a case of a set-top box for the digital satellite broadcast, the digital CATV, or the digital terrestrial broadcast, it becomes possible to realize this data forwarding by formatting the received data into a format of a physical network.
According to another aspect of the present invention, there is provided a network inter-connection node for connecting at least two physical networks including an IEEE 1394 bus and transmitting an information data received from one physical network to another physical network, comprising: a reception unit for receiving a first control message from said one physical network, the first control message containing an address information of a data transmission destination, and a first header/channel information dependent on said one physical network; a first transmission unit for transmitting a second control message to said another physical network when the reception unit receives the first control message, the second control message containing the address information and a second header/channel information dependent on said another physical network which is obtained from the address information; a memory unit for storing a correspondence between the first header/channel information and the second header/channel information, at least one of the first header/channel information and the second header/channel information including an isochronous channel number or a register offset indicating an isochronous channel of the IEEE 1394 bus; and a second transmission unit for obtaining the second header/channel information corresponding to the first header/channel information according to the correspondence stored in the memory unit when the information data containing the first header/channel information is received from said one physical network, attaching the second header/channel information to the information data, and transmitting the information data to said another physical network.
In this aspect of the present invention, it becomes possible to carry out the transmission of arbitrary data with respect to the receiving node belonging to arbitrary distanced network (a physical network to which the transmitting node does not belongs), under the environment in which the 1394 buses or the 1394 bus and arbitrary physical network are inter-connected.
Namely, in the inter-connected networks in which the 1394 buses or the 1394 bus and arbitrary physical network are inter-connected, it is possible to ascertain the destination node ID or channel number and the destination address of the destination node (which can be the network layer address such as IP address or the datalink layer address such as 1394 address or MAC address) which are the header information of the first physical network to which the data will be transferred later, from the neighboring node on the side of the IEEE 1394 bus which is the first physical network. Then, from this information, it is possible to notify a correspondence between the header/channel information to be used at the second physical network (virtual connection identifier, or destination node ID or channel number, or MAC address, etc., in the second physical network) and the destination address (the address information), to the neighboring node on the second physical network side (or conversely, the information from the second physical network side is notified to the first physical network side).
In addition, by referring to the header/channel information (channel number, destination node ID, virtual connection identifier, MAC address, etc.) of one physical network alone, it becomes possible to transfer the data by attaching (or converting) the header/channel information (channel number, destination node ID, virtual connection identifier, MAC address, etc.) of another physical network, so that the considerably fast processing becomes possible even between the 1394 bus and the other arbitrary physical network.
Moreover, at least one of the first header/channel information and the second header/channel information includes an isochronous channel number or a register offset indicating an isochronous channel of the IEEE 1394 bus, so that it becomes possible for the relay device to directly convert the isochronous channel number of the IEEE 1394 bus to the header/channel information (virtual connection identifier, isochronous channel number, MAC address, etc.) of the (another) second physical network (or vice versa). Consequently, especially in a case where the end-to-end data transfer by the datalink layer switching is desired as in a case of the transfer of data that requires the communication quality, it becomes possible to realize this data transfer by using the isochronous channel of the IEEE 1394 bus and using the channel number in a similar manner as the virtual connection identifier (such as VPI/VCI of the ATM).
Also, in this aspect of the present invention, said another physical network may be an Ethernet or a token ring or a FDDI, and the second header/channel information may indicate a MAC address.
Also, in this aspect of the present invention, said one physical network may be an Ethernet or a token ring or a FDDI, and the first header/channel information may indicate a MAC address.
In these cases, it becomes possible to recognize the header value and its attribute and communication quality on the 1394 bus side by providing the correspondence table and the conversion table based on the MAC address value, or conversely, to recognize the header information value (header/channel information depending on the second physical network) on the second physical network (another physical network) side and its attribute and communication quality by providing the table based on the header information value of the 1394 bus. Consequently, it becomes possible to carry out the data forwarding to the facing network side by the datalink layer processing alone, and the fast forwarding processing becomes possible. For this reason, it becomes possible to use the various frame schemes using MAC address as the transmission scheme of the second physical network.
Also, in this aspect of the present invention, said another physical network may be an ATM network, and the second header/channel information may indicate a VPI/VCI.
Also, in this aspect of the present invention, said one physical network may be an ATM network, and the first header/channel information may indicate a VPI/VCI.
In these cases, it becomes possible to recognize the header value and its attribute and communication quality on the 1394 bus side by providing the correspondence table and the conversion table based on the VPI/VCI value, or conversely, to recognize a value of the VPI/VCI value (header/channel information depending on the second physical network) and its attribute and communication quality by providing the table based on the header information value of the 1394 bus. Consequently, it becomes possible to carry out the data forwarding to the facing network side by the datalink layer processing alone, and the fast forwarding processing becomes possible. For this reason, it becomes possible to use the ATM as the transmission scheme of the second physical network (another physical network).
According to another aspect of the present invention, there is provided a data transmitting node connected with a network, comprising: a first transmission unit for transmitting a control message in a case of transmitting information data to a receiving node connected with another network, the control message including a first MAC address information of a data transmission destination, and a second MAC address information to be attached to the information data; and a second transmission unit for transmitting the information data containing the second MAC address information, to the receiving node.
In this aspect of the present invention, it becomes possible to explicitly notify a transfer target of the received data to a network connection device on a communication path, in such a manner that the information data entering with that second MAC address at the physical network interface to which this control message is entered will be data destined to that data transmission destination first MAC address.
In addition, it also becomes possible to explicitly notify that, for the information data entered with that second MAC address, the similar control message exchange is to be carried out at the subsequent hops and the packet/frame routing should be carried out by referring to the MAC address alone.
Also, in this aspect of the present invention, the control message may command to a network inter-connection node for connecting said network and a next network a registration of a correspondence between the second MAC address information and a header/channel information dependent on the next network.
This defines the operation of the control message in this aspect of the present invention.
Also, in this aspect of the present invention, the data transmitting node may further comprises: a reception unit for receiving digital video and/or digital audio data; wherein the second transmission unit transmits the digital video and/or digital audio data received by the reception unit as the information data, by formatting the digital video and/or digital audio data into a transmission format for said network.
In this aspect of the present invention, in a case of receiving the raw or MPEG coded video/speech data and forwarding the received data to a specific receiving node, as in a case of a set-top box for the digital satellite broadcast, the digital CATV, or the digital terrestrial broadcast, it becomes possible to realize this data forwarding by formatting the received data into a format of a physical network.
According to another aspect of the present invention, there is provided a network inter-connection node for transmitting information data received from one network to another network, comprising: a reception unit for receiving a first control message from said one network, the first control message containing a first MAC address information of a data transmission destination, and a second MAC address information; a first transmission unit for transmitting a second control message to said another network when the reception unit receives the first control message, the second control message containing the first MAC address information, and a third MAC address information which is obtained from the first MAC address information; a memory unit for storing a correspondence between the second MAC address information and the third MAC address information; and a second transmission unit for obtaining the third MAC address information corresponding to the second MAC address information according to the correspondence stored in the memory unit when the information data containing the second MAC address information is received from said one network, attaching the third MAC address information to the information data, and transmitting the information data to said another network.
In this aspect of the present invention, in the bridge network in which two or more physical networks are inter-connected, it is possible to ascertain the header information (the destination MAC address in the first physical network) of the first physical network (one physical network) to which the data will be transferred later and the destination address of its destination node (the MAC address information: the final destination MAC address), from the neighboring node of the previous hop. Then, from this information, it is possible to notify a correspondence between the header information (the destination MAC address in the second physical network) to be used at the second physical network (another physical network) and the destination address (the MAC address information: the final destination MAC address), to the neighboring node.
In addition, by referring to the header information (the destination MAC address in the first physical network) of said physical network alone, it becomes possible to transfer the data by attaching (or converting) the header information (MAC address) of the second physical network, so that the considerably fast processing becomes possible even between different types of networks. Here, the MAC address may be used as a logical value, that is, as the virtual connection identifier.
According to another aspect of the present invention, there is provided a network inter-connection node for connecting at least two physical networks, comprising: a request receiving unit for receiving from a first physical network an address resolution request for resolving a datalink layer address from a network layer address; a forwarding unit for forwarding the address resolution request with respect to a connected physical network other than the first physical network; a response receiving unit for receiving from a second physical network a first address resolution response corresponding to the address resolution request forwarded by the forwarding unit; a registration unit for registering a correspondence between the network layer address and the second physical network into a routing table, by referring to a network layer source address or a network address contained in the first address resolution response; and a response transmitting unit for transmitting to the first physical network a second address resolution response corresponding to the address resolution request received by the request receiving unit, by inserting a datalink layer address of said network inter-connection node device as a resolved address.
In this aspect of the present invention, when the first physical network and the second physical network are the networks using different address systems (such as the Ethernet and the IEEE 1394, for example), or when they are networks using the same address system which are however connected without using a bridge connection, it becomes possible to carry out a delivery of a packet to a desired node by specifying an address of this network inter-connection node as a packet destination with respect to a node which transmitted the address resolution request and carrying out the routing of a packet received at this network inter-connection node.
In addition, in this aspect of the present invention, the network layer address learning function is provided, so that it is possible to deal with a case where an entry or withdrawal of a node with respect to a network is to be made dynamically.
Also, in this aspect of the present invention, the network inter-connection node device may further comprises a transfer unit for transferring a received packet to a physical network registered in the routing table, according to a network layer destination address of the received packet.
Also, in this aspect of the present invention, the response transmitting unit may activate the forwarding unit when a network layer address contained in the address resolution request received from the first physical network is not a network layer address of said network inter-connection node device and not registered in the routing table, and transmit the second address resolution response otherwise.
Also, in this aspect of the present invention, the first physical network and the second physical network may be operated by different datalink protocols.
According to another aspect of the present invention there is provided unication device connected with a network of broadcast type (such as IEEE 1394), comprising: a reception unit for receiving a first message which is a control message for bandwidth reservation with respect to a network layer data flow, including a first identifier for identifying the network layer data flow, from a second communication device connected with the network; an establishing unit for establishing a broadcast type channel (such as isochronous channel or asynchronous stream of IEEE 1394) on the network according to the first message received by the reception unit; and a transmission unit for transmitting a second message which contains at least a correspondence between a second identifier of the broadcast type channel established by the establishing unit and the first identifier of the network layer data flow, to the second communication device.
In this aspect of the present invention, in a control protocol for bandwidth reservation with respect to a network layer data flow such as RSVP in Internet, a node which received a control message (first message, which is PATH message or RESV message in the case of RSVP) reserves a broadcast type channel (such as isochronous channel or asynchronous stream of IEEE 1394) on that network, so that it is possible to reserve the required communication resource in a form of the broadcast type channel, and it becomes possible to realize communication with end-to-end communication resource reserved as should be realized by the network layer level signaling protocol.
In addition, the second message can also be used for realizing transfer to a next hop network without requiring a routing processing in the network layer, by referring only to a datalink transfer at a network boundary, that is an identifier of a datalink layer (such as an identifier of the broadcast type channel), and indirectly recognizing the network layer flow transferred by a channel having that identifier. The second message can also be used by a downstream node to prepare for receiving of the network layer flow from that channel, or by an upstream node to prepare for transmission of the network layer flow to that channel.
Also, in this aspect of the present invention, the first message may be a message for requesting bandwidth reservation, which is transmitted from the second communication device connected to a downstream direction of the network layer data flow.
In this case, an upstream side node of the network layer flow can realize the bandwidth reservation in a form of bandwidth resource reservation for the broadcast type network. Namely, an upstream side node of the network layer flow can realize this bandwidth reservation in response to a bandwidth reservation request from a downstream direction, as in a case of receiving RESV of RSVP as the first message.
Also, in this aspect of the present invention, the first message may be a message for notifying bandwidth to be used, which is transmitted from the second communication device connected to an upstream direction of the network layer data flow.
In this case, a downstream side node of the network layer flow can realize the bandwidth reservation in a form of bandwidth resource reservation for the broadcast type network. Namely, a downstream side node of the network layer flow can realize this bandwidth reservation in response to a control message for bandwidth reservation from an upstream direction, as in a case of receiving PATH of RSVP as the first message.
Also, in this aspect of the present invention, the communication device may further comprises: a second transmission unit for transmitting a message for requesting bandwidth reservation to the second communication device which is connected to an upstream direction of the network layer data flow.
In this case, it becomes possible to transmit a message for bandwidth reservation in the network layer such as RESV message of RSVP to the second communication device of the upstream side, so that it becomes possible to realize the end-to-end bandwidth reservation.
Also, in this aspect of the present invention, the transmission unit may transmit the second message in a form of writing into a register provided at the second communication device.
In this case, it becomes possible to realize a notification of the correspondence between the identifier of the established broadcast type channel and the identifier of the network layer data flow in a form of writing into register, which is a generally known means for transmitting control information in a network of broadcast type such as IEEE 1394. This correspondence is an information regarding the datalink layer channel, so that it is appropriate to use a register for transmitting datalink layer control information, and it becomes unnecessary to provide a mechanism for receiving and interpreting this correspondence in the network layer.
According to another aspect of the present invention, there is provided a communication device connected with a network of broadcast type, comprising: a register for registering a correspondence between an identifier of a broadcast type channel established on the network which is to be used in transmitting and receiving a network layer data flow and an identifier of the network layer data flow; and a transmission and/or reception unit for transmitting and/or receiving the network layer data flow through the broadcast type channel according to the correspondence registered in the register.
In this aspect of the present invention, it becomes possible to notify to another node or obtain from another node a correspondence between a broadcast type channel identifier of a broadcast type network (such as IEEE 1394) described in this register and an information regarding a flow that passes through that channel. This correspondence is an information regarding the datalink layer channel, so that it is appropriate to use a register for transmitting datalink layer control information, and it becomes unnecessary to provide a mechanism for receiving and interpreting this correspondence in the network layer.
By using this register, when a node having this register is a transmitting node, it becomes possible for another node of the broadcast type network to recognize which flow is going to be transferred through the broadcast type channel of the broadcast type network described in this register (which flow is to be transmitted by the transmitting node), by referring to this register.
Also, when a node having this register is a transmitting node, it becomes possible for this transmitting node to recognize which flow is going to be transferred through the broadcast channel of the broadcast type network described in this register (which flow is to be transmitted by the transmitting node), as another node of the broadcast type network writes the correspondence into this register.
Also, when a node having this register is a receiving node, it becomes possible for this receiving node to recognize which flow is going to be transferred through the broadcast channel of the broadcast type network described in this register (which flow is to be received by the receiving node), as another node of the broadcast type network writes the correspondence into this register.
Also, this register may have a field for distinguishing transmission and reception. By means of this, it becomes possible to clearly indicate whether this register is to be used by the transmitting node or the receiving node.
According to another aspect of the present invention, there is provided a communication device connected with a network of broadcast type, comprising: a reception unit for receiving a subscription request for a network layer multicast address from a second communication device connected with the network; an establishing unit for establishing a broadcast type channel on the network in response to the subscription request received by the reception unit; a notification unit for notifying at least a correspondence between an identifier of the broadcast type channel established by the establishing unit and the network layer multicast address, to the second communication device; and a transmission unit for transmitting data destined to the network layer multicast address to the broadcast type channel established by the establishing unit.
In this aspect of the present invention, the isochronous channel for transmitting the corresponding network layer multicast is established by an IGMP router which receives the subscription request for that multicast address, so that it becomes possible to prevent communication resource within the network from being wasted by establishing a plurality of channels with respect to the identical multicast address.
Also, by notifying the correspondence between the identifier of the established broadcast type channel and the network layer multicast address to the second communication device, it becomes possible to notify a channel from which the multicast data can be received to the second communication device (receiving terminal), and in addition it becomes possible to accommodate a plurality of receiving terminals through a single channel because the broadcast type channel is used.
Also, in this aspect of the present invention, the communication device may further comprises: a second reception unit for receiving from the second communication device a request for reservation of bandwidth required in receiving the data destined to the network layer multicast address from the second communication device; and a reservation unit for reserving bandwidth of the broadcast type channel established by the establishing unit in response to the request received by the second reception unit.
In this case, it becomes possible to realize the transmission in a form that guarantees communication quality of the multicast.
According to another aspect of the present invention, there is provided a communication device, connected with a network of broadcast type, for transmitting data destined to a network layer multicast address, comprising: a reservation unit for reserving bandwidth for a broadcast type channel; a first transmission unit for transmitting the data destined to the network layer multicast address by using a period or connection for which the bandwidth of the broadcast type channel on the network is not reserved; and a second transmission unit for transmitting the data destined to the network layer multicast address by switching the period or connection used in the first transmission unit to a period or connection for which the bandwidth of the broadcast type channel is reserved, when the bandwidth is reserved for the broadcast type channel by the reservation unit.
In this aspect of the present invention, in a case of switching the network layer multicast packet transmission from a form of not reserving bandwidth to a form of reserving bandwidth, it becomes unnecessary to request the reservation of both the broadcast type channel and the bandwidth to a manager which is managing communication resource (such as isochronous resource manager in IEEE 1394) again, as required conventionally. Namely, it is possible to realize this switching by simply sending packets for the broadcast type channel that is already reserved as communication resource into the first transmission unit. The same also applies to the switching in the reserve direction (from a form of reserving bandwidth to a form of not reserving bandwidth).
Also, in this aspect of the present invention, an identifier of the broadcast type channel to which the data are outputted from the second transmission unit when the bandwidth is reserved by the reservation unit may be identical to an identifier of the broadcast type channel to which the data are outputted from the first transmission unit when the bandwidth is not reserved.
In this case, it becomes possible to prevent wasteful use of the broadcast type channel. In particular, for the datalink in which channel resource is relatively limited such as IEEE 1394, it becomes possible to share the same channel among the network layer multicast packets to be transmitted in a form of reserving bandwidth and multicast packets to be transmitted in a form of not reserving bandwidth, so that the efficient utilization of communication resource can be realized.
Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.